PROJECT SUMMARY This proposal aims to develop a therapeutic capable of preventing and treating the severe sinus inflammation associated with chronic rhinosinusitis (CRS). CRS is a debilitating inflammatory disease of the sinuses that impacts over 40 million Americans and substantially diminishes the quality of life and productivity of affected patients. From 2007 to 2011, the total US health care expenditure to treat patients with CRS increased from $9 to $64 billion USD, with a corresponding rise in surgical treatment for those patients who fail current medical management. CRS is characterized by massive inflammatory cell infiltration and increased cytokine/chemokine production. Therapy development should therefore be focused on inhibiting the mechanisms underlying the initiation of these inflammatory responses with the ability to be delivered efficiently by high volume saline irrigation known to improve mucosal penetration. GlycoMira Therapeutics, Inc. (GMTI) is developing a glycosaminoglycan-based anti-inflammatory compound (GM-0111) for CRS that is polyanionic, giving it excellent solubility in saline. Our work has shown that GM-0111 is safe, efficiently penetrates the sinuses, and effectively prevents acute sinus inflammation by blocking neutrophil activation and mast cell infiltration into the sinus mucosa. GM-0111 additionally inhibits important early pro-inflammatory signaling molecules, such as Toll-like receptors and selectins, resulting in decreased inflammatory mediator production. Based on our findings, we hypothesize that GM-0111 can prevent the development and progression of CRS by inhibiting inflammatory cell chemotaxis and activation within the sinuses, thereby reducing inflammation. Chemokines RANTES and eotaxin-2 are elevated in patients with CRS and are important in recruiting mast cells (early effector cells) and eosinophils (late effector cells), which favor a therapeutic-resistant state of inflammation. We will first test our hypothesis (Aim 1) by determining whether GM-0111 can inhibit chemokine-mediated activation of human mast cells, eosinophilic cells, and chemokine receptor knockdown cells (negative control), measuring intracellular calcium flux, proliferation, and chemotaxis in the absence and presence of recombinant chemokine. These studies will provide inflammatory mechanism-focused results for therapy translation to CRS. We will then test the feasibility of GM-0111 to prevent and treat CRS in vivo using a mouse model of CRS (Aim 2). Applying two dosing regimens, we will approach this goal by administering GM-0111 (1) prior to and (2) after establishing chronic sinus inflammation. Sinus tissues will be examined for histological characteristics (inflammatory cell infiltration, secretory cell hyperplasia, mucous secretion, and mucosa thickening) and tissue inflammatory biomarkers (mast cell tryptase, eosinophil myeloperoxidase, RANTES, and eotaxin-2). These studies will provide crucial preclinical data supporting GM-0111 as a therapeutic aimed at preventing and treating sinus inflammation in patients with CRS, moving towards commercialization in a market with tremendous unmet needs to improve the lives of millions of Americans.